RO membranes, reducing differential pressure (DP)

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I need proSupport regarding Membrane Clean-In-Place  (CIP) . 

What could cause be after CIP that the DP didn't decrease much? 

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9 Answers

  1. IF CIP is done properly with proper chemicals diff pressure has to come down resulting into better permeate flow rate... Depending upon capacity, Raw water Analysis, and plant recovery... Mail your details on kunjesh@januswater.com. for further consultancy.

  2. How much is the membrane age? If the CIP procedure has been selected properly for the special type of foulant, then it is possible that the membranes have reached the upper limit of their shelf life (normally 3-5 years). In addition, some manufacturers say that each CIP affects the performance of membranes so that they will not be alike the fresh installed ones.

    1 Comment

  3. Your issue is most likely due to organic or biofilm buildup on the membrane surface. CIP may be less effective depending on the method used. More information is required regarding the process and current method of CIP used to clearly understand the problem.  

    Answered on by

    1 Comment

    1. Hi Troy,   Regarding our method normally we usening first step biocide for two hrs recycltion then we go for high PH Then low PH Each socking and recycltion 1hr

  4. First of all, you will need to know what type of contamination you have in order to select the proper cleaning!

    Answered on by

  5. Your  question  is not  complete you must mention type of feed water and their character ,pre treatment, all parameter before and after cleaning and cleaning solutions and strategy to evaluate membrane performance 

  6. If gentle cleaning does't help go for harshest cleaning-Ref. Netto Hydranautics TSB107

    If still there is no improvement, plan for membrane replacement.

    Do autopsy study of the fouled membranes and take action to prevent. 

  7. High DP is due to a reduction in the open area for the feed flow. As the other commenters have suggested this could be due to an inadequate cleaning procedure. It could also be due to entrance of non-dissolvable materials (bacteria, silt, sand) into the elements. How are your elements arranged? Are you seeing the same type of DP across all of the vessels in the array, or are you seeing higher DP in either the first or last vessel? In the last vessel it is more likely to be precipitation of some compound from the feed water as the concentration increases. In the first vessel, and especially in the first element, it is likely to be something coming into the element with the feed. Could there have been construction debris left in the cleaning tank or piping?

    1 Comment

    1. Hi Pat 

      Thanks for your coment, Actully our RO is two stags and the DP which am talking about is 1st stag and it's commen for all 1st sags vesals. . Even we using same method of cip in 2nd stage and we geting good resultsa

  8. I would check your cleaning procedure. Were pH's maintained in the correct range through out the CIP. Any problems with the chemical feed pumps. Were the chemicals mixed properly?

    If the CIP was good, there is likely more fouling than expected and soak time, air scour, ect...will need to be adjusted.

    Did the feed water change? Could you have a new kind of fouling.

    Check with the manufacture

    1 Comment

    1. Thanks Mark

      Normaly we start with biocide 

      Then we use high ph 11.4-11.7

      Recyclation and sock 1hr each 5 tims

      Then we use low ph 3.5 - 2.3

      Same as high ph procedure

      And between each slution there is flushing step

      Also we dump the first water of each slution 

       

      Am wondring if the wither temp is effcting also